Electrically controllable inductor

Abstract

An apparatus for providing an electrically controllable inductor which uses a first and a second magnetic core (20, 24) spaced apart from one another. A DC bias coil (22) is wound on the first magnetic core (20). An inductor coil (26) is wound on both the first magnetic core (20) and the second magnetic core (24). The inductance seen at terminal connections (80, 82) of the inductor coil (26) is variable in dependence upon a magnitude of a flow of direct current through the DC bias coil (22). In one embodiment of the inductor, the first and the second magnetic core (20, 24) are each formed using a pair of U-shaped core segments (30, 32, 60, 62) located adjacent to one another. In this embodiment, the first and second magnetic core (20, 24) are located in an opposing relation to one another, with the DC bias coil (22) wound on inner legs (64, 72) of the first magnetic core (20) and the inductor coil (26) wound on inner legs (64, 72, 34, 44) of both the first and the second magnetic core (20, 24). A system is provided employing the electrically controllable inductor in combination with one or more other components (100).

What is claimed is: 
     
       1. An electrical system comprising: a) an electrically controlling inductor having a first magnetic core;   a second magnetic core proximate to the first magnetic core;   a first coil wound on the first magnetic core; and   a second coil wound on both the first magnetic core and the second magnetic core so as to share a winding path with the first coil and form an independent winding path about the second core;   wherein an inductance of the second coil is varied in dependence upon a flow of direct current through the first coil; and the inductance is variable over a range of inductances; and     b) one or more capacitors.   
     
     
       2. An electrical system comprising: a) the electrically controlled inductor having a first magnetic core;   a second magnetic core proximate to the first magnetic core;   a first coil wound on the first magnetic core; and   a second coil wound on both the first magnetic core and the second magnetic core so as to share a winding path with the first coil and form an independent winding path about the second core;   wherein an inductance of the second coil is varied in dependence upon a flow of direct current through the first coil; and the inductance is variable over a range of inductances; and     b) a transformer selected from the group consisting of: one or more zig-zag transformers; one or more isolation transformers; one or more auto transformers; and combinations thereof.   
     
     
       3. An electrical system comprising: a) an electrically controlled inductor having a first magnetic core; a second magnetic core proximate to the first magnetic core;   a first coil wound on the first magnetic core; and   a second coil wound on both the first magnetic core and the second magnetic core so as to share a winding path with the first coil and form an independent winding path about the second core;   wherein an inductance of the second coil is varied in dependence upon a flow of direct current through the first coil; and the inductance is variable over a range of inductances; and     b) one or more inductors selected from the group consisting of: one or more variable inductors; one or more fixed inductors; and combinations thereof.   
     
     
       4. The electrical system of claims 1-3 further comprising switch gear in combination therewith. 
     
     
       5. An electrical system comprising: an electrically controlled inductor having a first magnetic core;   a second magnetic core proximate to the first magnetic core;   a first coil wound on the first magnetic core; and   a second coil wound on both the first magnetic core and the second magnetic core so as to share a winding path with the first coil and form an independent winding path about the second core;   wherein an inductance of the second coil is varied in dependence upon a flow of direct current through the first coil; and the inductance is variable over a range of inductances, the electrically controlled inductor being in series with one or more semiconductor devices.     
     
     
       6. An electrical system comprising: an electrically controlled inductor having a first magnetic core;   a second magnetic core proximate to the first magnetic core;   a first coil wound on the first magnetic core; and   a second coil wound on both the first magnetic core and the second magnetic core so as to share a winding path with the first coil and form an independent winding path about the second core;   wherein an inductance of the second coil is varied in dependence upon a flow of direct current through the first coil; and the inductance is variable over a range of inductances, the electrically controlled inductor being in parallel with one or more semiconductor devices.     
     
     
       7. An electrical system according to claims 1-3 and 5-6 in a system having one or more phases. 
     
     
       8. An electrical system according to claim 4 in a system having one or more phases. 
     
     
       9. An electrical system comprising: a) the electrical system of claims 1-3 and 5-6 in combination with: a system for reducing harmonics in a power line comprising: a shunt network coupled to the power line, the shunt network having at least one electrically controllable inductor, wherein the at least one electrically controllable inductor includes a first magnetic core, a second magnetic core proximate to the first magnetic core, a first coil wound on the first magnetic core, and a second coil wound on both the first magnetic core and the second magnetic core;   a distortion monitor, coupled to the power line, for making at least one distortion measurement; and   a processor, responsive to the distortion monitor, for applying a direct current to the first coil of the at least one electrically controllable inductor in dependence upon the at least one distortion measurement;   wherein the direct current acts to reduce the harmonics in the power line by varying an inductance of the at least one electrically controllable inductor.       
     
     
       10. The electrical system of claim 9 in a system which is configured to perform a filter function, the system being selected from the group consisting of: a DC system; an AC system; and combinations thereof. 
     
     
       11. The electrical system of claims 1-3 and 5-6 in combination with a voltage system selected from the group consisting of: a low voltage system; a medium voltage system; a high voltage system; and combinations thereof. 
     
     
       12. The electrical system of claim 4 in combination with a voltage system selected from the group consisting of: a low voltage system; a medium voltage system; a high voltage system; and combinations thereof. 
     
     
       13. The electrical system of claim 9 in combination with a voltage system selected from the group consisting of: a low voltage system; a medium voltage system; a high voltage system; and combinations thereof. 
     
     
       14. The electrical system of claims 1-3 and 5-6 in combination with a system in an environment selected from the group consisting of: an ambient environment; a cryogenically controlled environment; and combinations thereof. 
     
     
       15. The electrical system of claim 4 in combination with a voltage system in an environment selected from the group consisting of: an ambient environment; a cryogenically controlled environment; and combinations thereof. 
     
     
       16. The electrical system of claim 9 in a system which is configured to perform a filter function, the system being selected from the group consisting of: a wye system; a delta system; and combinations thereof.